1. Field of the Invention
This invention relates to a coating fluid for forming an oxide coating which is thermally stable and has good coating properties and a method for forming an oxide coating using the same.
2. Description of the Related Art
Heretofore, as a process for layer insulation of semiconductors such as IC, LSI, etc., processes for forming an oxide coating on a substrate by calcining hydrolyzed and condensed products of silanol compounds have been well known. Among these processes, a process using tetrafunctional silanes such as tetraethoxysilane (ethylsilicate), etc. has been most often studied, but according to such a process using tetrafunctional silanes only, there is a drawback that when a silica coating is formed by calcination, the resulting three-dimensional crosslinked structure is so dense and rigid that the resulting coating is thick to cause cracks. As a process for overcoming such a drawback, a process of cohydrolyzing bifunctional or trifunctional silanes together with tetrafunctional silanes is disclosed in Japanese patent application laid-open No. Sho 57-191219/1982, but according to such a process, there is also a drawback that a large quantity of carbon is contained in the resulting coating. If carbon is left in the coating after calcination, cracks are liable to occur in the coating at the step of semiconductor production. Further, in order to eliminate the carbon contained in the coating, calcination at high temperature of 500.degree. C. or higher is required and since the coating shrinks due to the elimination of carbon or the difference between the thermal expansion coefficient of the coating and that of a substrate such as silicon, aluminum, etc. after the elimination is so large, there is also a drawback that the coating is cracked.